Frame supported grid resistors

ABSTRACT

A grid resistor has a plurality of identical resistor support frames each defining a plane. The frames are stacked in alignment to form a hexahedron structure with levels of frames. Plates on the outer face of the hexahedron structure support the frames tightly against each other to maintain the hexahedron structure. Within each frame there is at least one ribbon of resistance material which is fanfolded providing a plurality of equally spaced, parallel, uniform linear lengths connected by U-shaped folds. The U-shaped folds have studs at the outer tips of the folds which engage holes in the resistor support frames. Bus bars selectively couple the resistors in each level to a pair of output terminals.

United States Patent t191 Kirilloff [52] U.S. Cl 338/295, 338/57, 338/58,

338/315 [5 l] Int. Cl. HOlc 1/02 [58] Field of Search 338/295, 315, 57, 58, 280

[56] References Cited UNITED STATES PATENTS 2/1966 Nuss 338/58 12/1970 DuBois, Jr. 338/57 [451 Dec. 31, 1974 Primary Examiner-E. A. Goldberg Attorney, Agent, or Firm-Buell, Blenko & Ziesenheim [5 7] ABSTRACT A grid resistor has a plurality of identical resistor support frames each defining a plane. The frames are stacked in alignment to form a hexahedron structure with levels of frames. Plates on the outer face of the hexahedron structure support the frames tightly against each other to maintain the hexahedron structure. Within each frame there is at least one ribbon of resistance material which is fanfolded providing a plurality of equally spaced, parallel, uniform linear lengths connected by U-shaped folds. The U-shaped folds have studs at the outer tips of the folds which engage holes in the resistor support frames. Bus bars selectively couple the resistors in each le'vel to a pair of output terminals.-

5 Claims, 4 Drawing Figures FRAME SUPPORTED GRID RESISTORS This invention relates to a resistor and in particular to a dynamic brake grid resistor used in locomotive cars.

Resistors used for dynamic braking of a locomotive car or other similar uses are: (i) subjected to excessive vibrations; (ii) have a confined space; and (iii) are generally air cooled by forced air from fans which adds to the vibration. One of the problems is being able to use a thin ribbon material for resistance and yet maintain the spacing and support for the ribbon material in stacked layers to allow air to freely pass through the resistors to cool them. The ribbon resistance must be securely supported because of the vibration from both the forced air and the locomotive movement on which the resistors are mounted. Various types of fanfolded resistors have been suggested, however, some of them lend themselves to cumbersome manufacture and are not very easily or readily replaceable in the event that one layer of resistance burns out.

`The invention deals with the concept of securing resistors in a layered stack which forms a hexahedron. Ribbon resistance elements used are secured at tips of fanfolds of the ribbon-like material. The tips of the fanfolds are in Contact or near contact with inner walls of supporting frames which support the ribbon resistors.

I provide a resistor having a pair of terminals comprising a plurality of resistor support frames each defining a plane and each having the same shape, the frames are stacked in alignment to form a hexahedron structure; means engaging the hexahedron structure and holding the support frames tightly against each other to maintain the hexahedron structure; resistor means positioned within the plane defined each by each resistor support frame; and means electrically coupling all of the resistor means between and to the terminals whereby a resistor is presented between the pair of terminals.

Other details, objects and advantages of this invention will become apparent as the following description of the present preferred embodiment proceeds.

In the accompanying drawings, I have shown a present preferred embodiment of practicing the invention in which:

FIG. l is an exploded isometric view ofa grid resistor showing six levels of resistor support frames;

FIG. 2 is a fragmented view of three fanfolded tips showing them in an isometric exploded view and their connection to a support frame;

FIG. 3 is a top plan view of three fanfolds showing their connection to the support frame; and

FIG. 4 shows a typical electrical schematic of the resistor. It is to be understood, however, that various connections can be made in a combination series/parallel arrangement at various levels to produce various resistance schematics.

Referring to FIG. l, the resistor is generally shown as l0. It comprises a plurality of resistor support frames l2, 14, 16, 18, 20 and 22 also referred to in the drawing as levels l, 2, 3, 4, 5 and 6, respectively. Each of these resistor support frames define a plane. Each of the resistor support frames 12-22 are positioned in vertical alignment to form a hexahedron structure. The hexahedron structure is held together by a plurality of plates 24, 26, 28 and 30. These plates are bolted together as shown in the drawing to form an outer hexahedron structure. The plates 24 to 30 have flanges 31, 32, 34, 36, 38 and 40. Between plates 28 and 30 and the ends of the support frames 12-22 are insulating plates 42 and 44. Rods 46 and 48 extend along end plates 28, 26, 30 and 24. Within each of the frames 12-22 there are a pair of resistors 50 and 52 shown in frame 12 which is at the top of the hexahedron. These resistors 50 and 52 are formed by a conductive ribbon material which is fanfolded thereby providing a plurality of equally spaced parallel uniform linear lengths connected by U- shaped folds. The U-shaped folds (FIGS. 2 and 3) have studs 54 which are connected to the tips 56 of the U- shaped folds. The studs 54 engage holes 58 in support frame 12. The tips 56 are in contact or near contact with the inner wall of the support frame 12.

In order to selectively couple the various ribbon resistors in each level of the hexahedron, bus bars 60 and 62 on one end are supplied and similar bus bars not seen in the FIG. 1 are supplied on the opposite end of the hexahedron. Terminal bars R1 and R2 couple the top layer and the bottom layer.

FIG. 4 shows a typical schematic of the resistances in the various levels. lt is to be understood, however, that this can change and can be selectively made to include varying combinations of series/parallel resistances.

Such an arrangement provides a resistor comprising a plurality of thin ribbon continuous fanfolded resistance elements in a rigid well-supported form. This is required because of the vibration due to the locomotive on which the resistor l0 is mounted and also the forced air from a fan (not shown) which forces air from the top of the FIG. 1 beginning at level 1 going throug level 6. As the resistances burn out due to heat, the plates 24-30 can be removed and the connections of the bus bars 60 and 62 can be disconnected and various levels can be removed by sliding them out from the structure proper and replacing them.

While I have shown and described an embodiment of my invention, it will be understood that this invention may be otherwise embodied within the scope of the following claims.

I claim:

l. A resistor having a pair of terminals comprising:

l. a plurality of resistor support frames each defining a plane and each having the same shape, the frames are stacked in alignment to form a hexahedron structure;

2. means engaging the hexahedron structure and holding the support frames tightly against each other to maintain the hexahedron structure;

3. resistor means positioned within the plane defined by each resistor support frame; and

4. means electrically coupling all of the resistor means between and to the terminals whereby a resistor is presented between the pair of terminals.

2. A resistor as recited in claim 1 wherein the means engaging the hexahedron structure includes a plate along each surface formed by the hexahedron, at least two of the plates have flanges engaging the outer support frames of the hexahedron structure, the plates are connected to form an outer hexahedron which conforms to the shape of the hexahedron structure formed by the support frames.

3. A resistor as recited in claim 2 wherein the resistor means includes a pair of resistors each formed by conductive ribbon material which is fanfolded providing a electrically coupling the resistor means includes a plurality of bus bars for selectively coupling the resistor means in various levels of the hexahedron.

5. A resistor as recited in claim 3 wherein the support frames are electrical insulating material. 

1. A resistor having a pair of terminals comprising:
 1. a plurality of resistor support frames each defining a plane and each having the same shape, the frames are stacked in alignment to form a hexahedron structure;
 2. means engaging the hexahedron structure and holding the support frames tightly against each other to maintain the hexahedron structure;
 3. resistor means positioned within the plane defined by each resistor support frame; and
 4. means electrically coupling all of the resistor means between and to the terminals whereby a resistor is presented between the pair of terminals.
 2. means engaging the hexahedron structure and holding the support frames tightly against each other to maintain the hexahedron structure;
 2. A resistor as recited in claim 1 wherein the means engaging the hexahedron structure includes a plate along each surface formed by the hexahedron, at least two of the plates have flanges engaging the outer support frames of the hexahedron structure, the plates are connected to form an outer hexahedron which conforms to the shape of the hexahedron structure formed by the support frames.
 3. A resistor as recited in claim 2 wherein the resistor means includes a pair of resistors each formed by conductive ribbon material which is fanfolded providing a plurality of equally spaced, parallel uniform linear lengths connected by U-shaped folds, the U-shaped folds have studs at the outer tips of the folds which engage holes in the resistor support frames, the pair of resistors are separated by a center strip of electrical insulating material.
 3. resistor means positioned within the plane defined by each resistor support frame; and
 4. means electrically coupling all of the resistor means between and to the terminals whereby a resistor is presented between the pair of terminals.
 4. A resistor as recited in claim 3 wherein the means electrically coupling the resistor means includes a plurality of bus bars for selectively coupling the resistor means in various levels of the hexahedron.
 5. A resistor as recited in claim 3 wherein the support frames are electrical insulating material. 